This invention relates to a magneto-optical recording medium for recording, reading and erasing information by using laser light, and more particularly to a magneto-optical recording medium having a high recording sensitivity, suited to improving a carrier-to-noise ratio (C/N) and having a large magneto-optical effect.
In recent years, as a medium for magneto-optical recording, rewritable optical system, rare-earth-transition metal amorphous thin films which provide a relatively larger Kerr rotation angle have been particularly noted. Among these amorphous thin films, particularly a Gd-Tb-Fe or Tb-Fe-Co system amorphous thin film provides a comparatively larger Kerr rotation angle so that reserch and development on this alloy system have been actively carried out (see, e.g., Japanese Patent Un-examined Application Laid-Open Nos. 58-73746, 58-159,252 and 59-159,510, or West German Patent Application Laid-Open DE-OS 3,309,483). However, it has been found that the conventional amorphous thin films, including these systems, provide a large modulation noise, because of the production of unwritable portions (inverse magnetized portions) at the centers of recording domains during recording and, therefore, an insufficient carrier-to-noise ratio (C/N) on reading.